Nanotubes and nanotube-derived films are implemented in a variety of electronic and sensing devices. Many of these devices require application of a voltage potential across individual, bundles, or networks of nanotubes. Therefore, an electrical contact is included in the device to provide the voltage across the nanotube. The ability to form stable, low resistance electrical contacts to the nanotube structures helps to enable reliable operation of these devices.
One example of electrical contacts coupled to nanotube structures includes preformed bottom contacts. Bottom contacts may be sensitive to electrode surface preparation and topography effects, typically offer limited surface contact area, and may only provide a relatively high contact resistance, and thus generally lack desirable characteristics for use with nanotube structures.
Another example of electrical contacts coupled to nanotube structures includes top side contacts formed by conventional deposition and patterning techniques. But top side contacts are also generally not applicable to nanotube structures because the top side contact metals may not be able to be etched with sufficient selectivity to avoid degrading the thin nanostructures located below. In addition, procedures for forming top side contacts, such as using lift-off techniques for example, are generally not compatible with state-of-the-art nanotube devices and manufacturing methods.